This disclosure relates generally to computer memory, and more specifically to writing a special symbol to a memory to indicate the absence of a data signal in the memory.
Memory technologies such as flash memory and phase change memory (PCM) benefit from iterative write techniques (commonly referred to as “write-and-verify”) which are comprised of a sequence of write and read operations. These techniques allow a controller for the memory to store a desired value with an increased accuracy since the read operations offer a feedback mechanism that can be used to reduce errors in the writing process. Such increased accuracy is particularly important when more than one bit per cell either in flash memory or PCM is desired. One drawback of write-and-verify techniques is that the iterative process consumes additional resources in the memory. For example, the write bandwidth gets reduced in a manner proportional to the number of attempts it takes to store a value in the memory.